In vitro binding of IgG in unfractionated RBC eluates and of IgG purified from RBC eluates to unselected homologous RBCs
| . | DAT . | IgG in Unfractionated Eluate . | IgG Purified From Eluate . |
|---|---|---|---|
| Patient 1 | ++ | +++ | +++ |
| Patient 2 | ++ | ++ | ++ |
| Patient 3 | +++ | +++ | +++ |
| Patient 4 | +++ | +++ | +++ |
| Patient 5 | ++ | ++ | ++ |
| Blood donor 1 | − | − | +++ |
| Blood donor 2 | − | − | ++ |
| Blood donor 3 | − | − | +++ |
| Blood donor 4 | − | − | +++ |
| Blood donor 5 | − | − | ++ |
| . | DAT . | IgG in Unfractionated Eluate . | IgG Purified From Eluate . |
|---|---|---|---|
| Patient 1 | ++ | +++ | +++ |
| Patient 2 | ++ | ++ | ++ |
| Patient 3 | +++ | +++ | +++ |
| Patient 4 | +++ | +++ | +++ |
| Patient 5 | ++ | ++ | ++ |
| Blood donor 1 | − | − | +++ |
| Blood donor 2 | − | − | ++ |
| Blood donor 3 | − | − | +++ |
| Blood donor 4 | − | − | +++ |
| Blood donor 5 | − | − | ++ |
IgG was eluted from the RBCs of 5 patients with WAIHA and 5 healthy blood donors. The DAT was positive with anti-IgG in the case of all patients, as indicated, and negative with anti-IgG in the case of healthy controls. Binding of IgG in the unfractionated eluate and of IgG purified from the eluate to homologous RBCs was assessed by means of an indirect Coombs assay at 2.3 ng/107 RBCs in the case of patient nos. 1 to 4 and donor nos. 1 to 4, and at 0.3 ng/107 RBCs in the case of patient no. 5 and donor no. 5. Agglutination was graded from − to +++ using a conventional grading system.